Liquid cooled resistor



Feb. 24, 1942- L. w. RICHARDSON LIQUID COOLED RESISTOR ,Filed July 16,1941 Ihvehtor: Lycurgus W Richardson,

Hi5 Attorney.

I Paternal-"ch24, 1942 UNITED STATES PATENT OFFICE- LIQUID COOLEDRESISTOR Lycurgus W. Richardson, Scotia, N. Y., assignor to GeneralElectric Company, a. corporation of New York Application July 1c, 1941,Serial No. 402,612

5 Claims. ,(01. 201-63) My invention relates to resistor devices of thetype comprising a tubular resistor element usually coated with a highresistance material, particularly to liquid cooled resistor devices, andthe object of the invention is to provide an improved, simple, andreliable device of this character.

Resistor devices comprising a thin walled tube of porcelain or the likehaving a high resistance coating thereon, or in some cases a wireresistance, or even a tubular element of resistance material such ascarbon, are commonly employed in radio transmitters, for example.Because of space requirements such resistors are often required to beoperated at ratings beyond the values at which they can be air cooledsufllciently and in these cases it is necessary to circulate a liquidcooling medium such as water or oil over their surface.

In resistors of the type above'mentioned, particularly as employed inradio transmitters or the like, the voltage drop from one end to theother may be several thousand volts and the resistors may be required tooperate in extremely high frequency circuits. These conditionsnecessitate that the coverings or housings provided for water or oilcooling of the resistance element be of high grade insulation materialand also that the space capacity of the assembly be as low as possible.

Difliculties have been encountered at times in the manufacture andoperation of water and oil cooled resistors. For example, it has beenfound difiicult in certain cases to make proper electrical connectionsto such resistors and to seal them against leakage without at the sametime subjecting the resistor elements or tubes, the insulating covers orhousings, and the mounting means to such strains that impaired operationresulted either when power was applied, because of thermal expansion, orafter a short. service period. Further, it has proved dimcult in certaincases to provide a liquid cooled resistor as- One assembly part isconstituted by the removably inserted in such manner that oil or watermay be circulated over its surface. The latter assembly part comprisesan insulating housing having enlarged end portions secured liquid tightto members slidable on the resistor terminal members and cooperatingtherewith to form liquid tight joints between the two as,- sembly parts.

The novel features which are considered to be characteristic of myinvention are set forth with particularity in the appended claims. Myinvention itself, however, both as to its organization and method ofoperation together with further objects and advantages thereof may bestbe understood by reference to the following description taken inconnection with the accompanyingdrawing wherein Fig. 1 is a sideelevatlcnal view partly in section of a liquid cooled resistor device inaccordance with my invention; and Figs. 2 and 3 illustrate modificationsof the resistor device of Fig. l.

Referring to Fig. 1, a resistor element l is shown therein which may beconstituted as inusual practice by a thin-walled tube of porcelain orother suitable insulator having on its surface a resistance which ispreferably a coating of high resistance metallic material but which maybe in the form of a winding. To aid in making reliable electricalconnection to the resistance material, bands 2 of highly conductivematerial such as silver are deposited on the resistor element l at theends thereof.

' Two terminal members 3 are provided for the resistor element I whichare of slightly larger diameter than the latter element and each ofwhich has a thin-walled cup-shaped portion 4 turnedor otherwise formedin its inner end into which the resistor element is adapted to fitloosely. The terminal members 3 are turned down or otherwise formed attheir other ends to provide hose connections 5, and holes, as 6 and I,are provided for the flow of cooling liquid to and from the outside ofthe resistor element I. If a tubular resistor element formed entirely ofresistance material such as carbon is used, it will of course benecesary to provide holes to pass the cooling liquid both on the outsideof the tube and through the center also. i

In assembling the sub-assembly or assembly part comprising the tubularresistor element I and the terminal members 3, the two latter membersare placed respectively over the opposite ends of the resistor elementand are then held in a jig (not shown) in such a manner that thelongitudinal center line of one terminal mem- 1 expansion whensolidifying.

In forming and assembling the other sub-assembly or assembly partconstituting a covering member for the above-described assembly partwhich includes the resistor and its terminal members, an insulator tube8, preferably glass of the "Pyrex type, having an internal diametergreater than the outside diameter of resistor I by an amount sufficientto provide room for the efflcient flow of the cooling liquid, is heatedand upset at its ends to form ridges or flanges I on the outside of thetube. The shape and size of these ridges may be controlled fairlyaccurately by the use of a graphite-mold (not shown). The tube 8 is thenground if necessary across each end to produce flat end surfaces Itaccurately parallel to each other and at right angles to the axis of thetube, and also to ensure that the tube is of accurate length. Theoutside surfaces II of the .ridges 9 are then ground if necessary to anaccurate diameter, these surfaces being in line with each other andparallel to the tube axis.

Two shells II of suitable material as brass or copper are provided, tobe connected to the ends of glass tube 8. Each shell includes acylindrical portion it having at its innerend a flange portion I whichis adapted to be a close sliding flt on the terminal members 3 and is ofslightly larger diameter than that of the ground ridges or flanges 9 ofglass tube 0. From the flange portions II extend rings or sleeves I!which may be in the form of thin soft tubing brazed to theflanges I4,or, as shown in the flgure, may be formed as an integral part of thelatter flanges.

glass housing tube I connected liquid tight to the two shell members II,with the shell members I! on the corresponding terminal members I.Stufling boxes at the ends of the device each comprise one of the shellmembers If, packing II, collar It, and spanner nut 20. These stuffingboxes provide a sliding liquid-tight joint between the twosub-assemblies.

It is desirable that the shell members ll be used as terminals forconnection to outside circuits (not shown), but since the metal surfacesof the resistor terminal members I and of the shell members I: are notclamped together a reliable electrical contact does not exist betweenthe resistor and the shell'members I2. It is therefore desirable to addflexible connectors II which may be soldered to the shell members I2 andfastened to the resistor terminal members 3 by screws or also bysoldering. The complete resistor device may be conveniently mounted inthe transmitter, or other apparatus of which it forms a part, by meansof clamps (not shown) connected to the cylindrical main body portions"To: the shell members I2.

change or replace a resistor as thus mounted in the transmitter thecomplete assembly may be removed from the clamps or other mounting meansafter disconnecting the hose from the hose connections. Or, if desired,the assembly part comprising the glass housing 8 and the shell membersI2 connected thtereto may' be left clamped in place in the transmitter.In this case, after removing the hose and the flexible connectors 2i andloosening the spanner nuts 20, the sub-assembly consisting of resistor Iand its terminal members I may be pulled out from one end of thesub-assembly comprising glass housing I and its shell members I2. Toreplace a resistor thised sequence of operation for removal is reveReferringto Fig. 2 the resistor device shown On the face of the flangeportion II of the shells I2 annular projections I are provided which,as-

shown in figures, may be in the form of a ring of small diameter wiretinned to the surface of the shell, or may be an annular projectionformed integralwith and machined from this surface.

As a part of the means for insuring a liquid tight joint between theglass tube 8 and the shell gaskets I I are provided preferably of asuitable grade of the material known as Neoprene? or other oilproof,long aging artificial rubber, fltted within the rings or sleeves I5.

To assemble the assembly part comprising the covering member whichincludes the glass housing tube 8 and the metal shells I2, these partsare placed in the proper order on a metal rod (not shown) having thesame outside diameter as the terminal members I and are then clampedtogether with suchend pressure that the annular projections or wireringsI. are completely embedded in the soft gaskets II. While the parts areheld in this position the thin soft tubing inl'ig. 2 the resistorterminal members. 22, instead of being turned from solid stock areassembled from two pieces of tubing, one of these, 28, constituting themain body of the terminal, into a cup-shaped portion II of which theends of the resistor I is soldered, and the other tube, 24, being thehose connection. A disk, flfwithin tube 23 closes the end of theresistor tube I, and a second disk, 21, supporting the hose connection,is provided at the outer end of the terminal member.

Holes II in the tube 23 connect the interior of this tube to the spacebetween the resistor element-I and the glass housing tube I. Theresistor terminal construction above described, and illustrated in Fig.2, is in many cases preferable as the resistor assembly part ismaterially lightened sleeves I 5 are spun tightly over the flanges 0 ofglass tube 8. The assembled covering memthe sub-assembly or assemblypart comprising the and cost in quantity production is reduced.

Referring to Fig. 3, the resistor device shown therein is essentiallythat of Figs. 1 and '2 except that Big. 3 is employed when it is desiredthat both the inlet and outlet for the cooling liquid be at one end ofthe device instead of at opposite endsasin-Figs. 1and2. Inllg.3thecooling liquid passes into one of the resistor terminal members,2!, as through a hose connection or tube II, through openings ll in thewall of the terminal member into the space between the resistor elementI and the glass housing member I. through openings 32 and II of the.other terminal member 84, which includes an end wall or disk 3|, intothe space within the resistor element I, and out through a tube 38connected to an inner wall or disk 31 of the resistor terminal 28.

My invention has been described herein in particular embodiments forpurposes of illustration. It is to be understood, however, that the invntion is susceptible of various changes and modiflcations and that bythe appended claims I intend to cover any such modifications as fallwithin the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:.

1. In combination, a resistor element having a layer of conductivematerial thereon at each end thereof, terminal members into which saidends are secured, a housing of insulating material for said resistorelement having a flange at each end, stufling boxes slidable on saidterminal members and each including a shell having an annular projectionon the inner end thereof, gaskets between each of said shells and thecorresponding housing flange, and rings extending from each of saidshells and adapted to be spun over said housing flanges to compress saidgaskets and to embed said annular projections therein, said terminalmembers having cooling liquid conducting openings formed therethroughfor conducting said cooling liquid in contact with said resistorelement.

2. In combination, a cylindrical resistor element having a layer ofconductive material on each end thereof, cylindrical terminal members ofslightly larger diameter than said resistor element and each having acup-shaped portion into which the corresponding end of said resistorelement is secured, a cylindrical housing of insulating material forsaid resistor element having a flange at each end, stufling boxes oneach of said terminal members each including a shell having a flangeportion adapted to be a close sliding fit on the corresponding terminalmember, an annular projection on each of said shell flange portions, aring of gasket material between each of said shell flange portions andthe corresponding housing flange, and thin sleeves connected to saidshell flange portions and each adapted to be spun over the correspondinghousing flange to compress said rings and to embed said annularprojections therein, said terminal members having cooling liquidconducting openings therethrough for conducting said liquid in contactwith said resistor element.

3. In combination, a resistor element having a layer of conductivematerial thereon at each end thereof, terminal members each comprising atube having an end portion into which the corresponding end of saidresistor element is secured and a disk fastened within said tubeadjacent to and'closing the end of said resistor, a tubular housing ofinsulation surrounding said resistor element and having a flange at eachend, stuffing boxes on said terminal members each having an annularprojection, gaskets between each of said stufllng boxes and thecorresponding housing flange, said stufling boxes each having a thinannular extension adapted to be spun over the corresponding flange toembed the corresponding annular projection within the correspondinggasket, said tubes having cooling liquid conducting openings forconducting said liquid in contact with said resistor element.

4. In combination, a hollow resistor element having conductive materialthereon at the ends thereof, terminal members into which said ends aresecured, an insulating housinghaving end flanges, stufling boxes on saidterminal members each having an annular projection, a gasket betweeneach stufling box and the corresponding housing flange, annularextensions on said stuffing boxes adapted to cooperate with said housingflanges to compress said gaskets and to embed said annular projectionstherein, one of said terminal members having cooling liquid conduct-.ing tubes connected thereto communicating respectively with the spacewithin said resistor and with the space between said housing and saidresistor, the other terminal member having openings therein forconducting said cooling liquid between said spaces.

5. In combination, a hollow resistor element having conductive materialthereon at the ends thereof, terminal members each comprising a tubehaving an end portion into which the corresponding end of said resistorelement is secured and a disk across said tube adjacent to the end ofsaid resistor element, an insulating housing having end flanges,stufling boxes on said terminal members each having an annularprojection, a gasket between each stuffing box and the correspondinghousing flange, annular extensions on said stumng boxes cooperating withsaid housing flanges to compress said gaskets and to embed saidprojections therein, one of said terminal members having cooling liquidconducting members connected thereto communicating respectively throughthe corresponding disk with the space within said resistor element andthrough the walls of the corresponding tube with the space between saidhousing and said resistor element, the other terminal member havingopenings in the corresponding disk and the walls oi the correspondingtube for conducting said cool ing liquid between said spaces.

I LYCURGUS W. RICHARDSON.

